What's Hot: Wired syncing! Slim design that still adds plenty of battery life.

What's Not: Power switch and battery lights aren't as convenient as the competition.

Whenever an iPhone battery case with a cool new gimmick comes out, I usually follow a process like this:

1. Be intrigued by the gimmick and buy the case.2. Try the case out for a week.3. Switch back to Mophie.

No matter how cool the gimmick (swappable batteries, a wide variety of colors, etc.), it seemed that the competition always made some foolish mistake that made the case pale in comparison to the de facto standard of Mophie - for example, you couldn’t charge the case and the phone at the same time, or the case would be impossible to put on and take off. I had reached the point of saying, “Just buy Mophie and don’t even bother with the gimmicks” - that is, until a case arrived that offers the one feature I always wanted.

Along Came a SpyderThe Spyder PowerShadow i5d is a pretty standard looking iPhone battery case, measuring 5.39" x 2.49" x 0.58" and adding 2.98 ounces of weight to your iPhone. It features press-through volume buttons and cut-outs for the power switch and silence/rotation lock switch. The headphone jack is accessible, though significantly recessed, so like many battery cases, a headphone extender cable is included. Although this is not the most elegant solution, the extender is more flexible and reliable than some of the competition, and it doesn’t cause the sound to cut out when jostled.

It is only available in black, although we found that the black model looked reasonably classy even on a white iPhone. It does not include any screen protection. The case is divided into two pieces, divided near the top of the case, and it fits snugly onto your iPhone.

The Spyder includes a 2,100 mAh battery that roughly doubles the battery life of your iPhone 5 or 5S. Adding 8 hours of talk time, 11 hours of video playback, or 44 hours of audio, the PowerShadow i5d can help keep you using your iPhone all day long, and then some.

Back in the days of the 30-pin Dock Connector, virtually all battery cases for iPhone 4S and earlier enabled syncing - simply plug in the cable, and the phone syncs with iTunes just as if you had plugged in the phone directly with a sync cable. However, when Apple switched to the Lightning Connector, this functionality disappeared (even on Mophie cases). You could plug the case into your computer with a cable, and the case would charge, but there was no data synchronization. You could, of course, use iTunes wireless syncing, but iTunes seems to have a lot of trouble detecting wireless devices, and even if you get it to work, syncing over WiFi generally takes somewhere in the neighborhood of… forever.

Since syncing functionality had abruptly vanished from all iPhone battery cases, I was beginning to think it was simply not possible on devices with a Lightning Connector. However, the Spyder PowerShadow i5d offers true wired syncing. That’s right: you can sync your iPhone over USB and even perform a System Update or Restore, all without removing the case. You can also charge the case and the phone and the same time.

As if that weren’t amazing enough, the i5d runs a victory lap around the competition by throwing in a sturdily made dock for you to rest your phone and case in. The dock is weighty and stable, and the i5d includes two different sets of connectors so that you can either rest the phone in the Dock, or connect a USB cable directly to the case (either way, you can charge and perform wired syncing).

Now, the i5d is not quite perfect: On Mophie cases, you can simply leave the case powered on, and it will both power your iPhone and allow recharging. Although theoretically you will get slightly higher runtime by first using up your internal battery and then turning on the Mophie to recharge it, if you prefer, you can simply leave the Mophie turned on at all times and literally forget about the power switch. Mophie cases also have charge lights that only turn on when you press the indicator button.

The i5d is not quite as slick - connecting it to your computer causes it to switch into “off” mode automatically. That means that whenever you disconnect it, you have to press and hold the power button to turn the case on (or you can wait until your internal battery is low). Additionally, the charge indicator lights on the i5d stay on whenever the case is powered on, instead of just popping up briefly when you press a button. These are minor inconveniences, but not enough to outweigh the major convenience of true wired syncing.

Shadow WarriorThe Spyder PowerShadow i5d is the first battery case I’ve seen for iPhone 5/5S that doesn’t have a step 3: I have no plans of switching back to my Mophie anytime soon. It might be nice if future versions of the case revised the operation of the power switch and charge lights, but nonetheless, if you have an iPhone 5 or 5S, this case is practically a must-have.